Method of recovering cymene obtained in sulfite-cellulose process



N. L. AKERBLOM.

METHOD OF RECOVERING CYMENE OBTAINED IN SULFITE CELLULOSEPROCESS.

APPLICATION FILED FEB. II, I9I8.

1,333,694. Patented Mar. 16, 1920.

2 SHEETSSHEET I.

N. L. AKERBLOM. METHOD OF RECOVERING CYMENE OBTAINED m SULFITE CELLULOSE PROCESS.

APPLICATION Fl LED UZB- H, I918.

Patented Mar. '16, 1920.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

NILS LEONARD AKERBLOM, OF-STOCKHOL'M, SWEDEN.

METHOD OF RECOVERING CYMENE OBTAINED IN SULFITE-OELLULOSE PROCESS.

'sulfite cellulosefactories and containing cymene and other hydrocarbons, resins and other constituents. This oily product is in the following description called cymene after its most valuable constituent.

In boiling sulfite cellulose, the gases escaping from the boilers during the boiling operation or after the same are led into receptacles containing .acid prepared for use in a subsequent boiling operation in orderto recover sulfurous aci and other gases. These gases also contain the cymene which is, thus, accumulated in the receptacle.

The present invention now has for its object the recovering of the cymene which is lighter than the acid and thus rises to the surface and floats as a thin layer on thesame. With this object in view the principal feature of my invention..consists in raising from time to time the surface of the liqul contained in the receptacle, increasing the thickness ofsaid layer by forcing it into a narrow portion of the receptacle, and leading-off the cymene from said narrow portion through suitable outlets. The raising of the surface of the liquid is executed by introducing into the receptacle acid or other liquid which has a higher specific gravity than cymene. This separating of the cymene may be executed in a second receptacle connected with that receptacle (here re ferred to as main receptacle) into which the gases are led from the boiler, and into which second receptacle is led a small quantity .of acid on which floats the layer of cymene which has been left in the main receptacle when emptying the same through an outlet at its. lower end. The separating of the cymene according to this invention I may also be performedin the main receptacle, provided that this one has a tapered upper portion or is provided with a narrow neck.

Another feature of my invention consists in performing the raising of the surface of Specification of Letters Patent. Patented Mar. 16, 1920.

Application filed February 11, 1918.

Serial No. 216,540.

the liquid stepwise, be. in suchja manner that first a rough regulating is executed by introducing acid or other heavier liquid into the receptacle until the surface of the liquid has been raised to or nearly to the taperedportion or neck, and then executing a fine'regulating of the raising of the surface in acid portion or neck by introducing acid, water or other heavy liquid through a more narrow conduit into the upper or lower portion of the receptacle.

Other features of my invention will be clear' from the following description of themethod, reference being had to the accompanying drawings schematically illustrating two different forms of apparatus.

Figure 1 shows a system of apparatus to be used in executing the invention. Fig. 2 shows another form of apparatus.

In- Fig. l themain receptacle A receives through the conduit B the gases from the boiler, the surface of the .liquid on which floats the cymene being then at I. Therewhere the liquid is assumed to rise to the level 1. After the valve P has been closed, the surface of the liquid is raised to level 2 (rough regulating) by introducing acid or other heavy liquid through the conduit C, the valve G provided in the same being then open. Then the valve G is closed and the valve H on the narrower tube D is' opened, so that acid from C is introduced into the upper narrow portion of the second receptacle Q. Instead of acid from C water or other liquid may be introduced into the tube D from a conduit F- provided with a valve 1. By this meansa very fineregulating of the raising of the layer of cymene within the upper narrow portion of the receptacle is rendered possible until the cymene flows off through the conduit L from which it is recovered practically free from acid.

According to Fig. 2 the cymene is sepa-v rated from the acid within the main receptacle A receiving gases from the boiler provided with a neck E in which the sepathrough conduit B. The main receptacle is rating take place. The surface of the liquid originally stands at 1 and is then raised to 2 by introducing acid from conduit G into the receptacle (rough regulating). Then acid from C or Water from F is introduced into the neck E where the previously thin layer of cymene becomes thicker and now rises in the neck and flows off through conduit L until the acid has been raised nearly to the level of the outlet, at which moment the valve T located in the conduit L is closed.

The difficulty of separating the cymene from the acid is due to the fact that the cymene is present in minute quantities and, consequently, that the layer of the same is very thin. Heretofore one has therefore from time to time tapped ofi? great quantities of acid together with cymene into large receptacles and accumulated them there until a sufliciently thick layer of cymene for being skimmed oil has been formed. Even after the skimming off of the. cymene the latter has contained great quantities of acid which it has been necessary to separate in some Way or other. The present invention renders it possible by simple means to separate the last drops of cymene practically free from acid. The cymene obtained in this way is, consequently, immediately ready for use. The minute quantities of acid which may be mingled With the same may readily be removedby adding a neutralizing agent, such as lime stone, chalk or lime.

The above method may of course also be used for separating under analogous conditions small quantities of any light liquid from a heavier liquid. I

Having now described my invention, what I claim and desire to secure by Letters Patent 1s:

1. The herein described method of re.-

covering cymene obtained in the sulfite cellulose process, consisting in leadlng gases from a cellulose boiler into a receptacle containing acid for a subsequent boiling operation, tapping 01f the greatest part of sald acid from the lower end of the receptacle, leadin off the remaining acid together with the cymene floating on the same to a second receptacle, raising the surface of the liquid in said second receptacle by introducinginto the same a heavier liquid than cymene, increasing the thickness of the layer of cymene by forcing it into a narrow portion of the receptacle and leading off said layer of cymene, substantially .as described.

2. The herein described method of recovering cymene obtained in the sulfite cellulose process, consisting in leading the gases from a cellulose boiler into a receptacle containing acid for a subsequent boiling operation, tapping ofi the greatest part of said acid from the lower end of said receptacle, leading 011' the remaining acid together with the cymene floating on the same to a second receptacle, raisin the surface of the liquid in said receptacle 'by introducing a heavier liquid than cymene through a conduit, increasing the thickness of the cymene layer by forcing it into a narrow portion of the receptacle by means of a heavier liquid than cymene introduced through a narrower conduit than the first mentioned one and leading off the cymene from the upper part of said narrow portion, substantially as described and for the purpose set forth.

In testimony whereof I have aflixed my signature in presence of two witnesses.

NILS LEONARD AKERBLOM.

\Vitnesses:

AXEL EHRNER, JAooB BAGGE. 

